Maintain timestamp of CSV File

We were having a scenario, where we had to fix few CSV field issues. But, we also wanted to retain timestamp. We used below script to fix the CSV and maintain the timestamp.

 $BulkLoadFolder = "C:\Projects\Sntrax\Bulkload\FilesToFix"  
 $Folder = "C:\FilesToFix\"  
 $filesList = Get-ChildItem -Path $Folder -Filter *.csv | select fullname | ForEach-Object { $_.FullName }  
 foreach($file in $filesList)  
 {   
     $newfile = $file.Replace("FilestoFix","FilestoFix\fixed")  
     #Get lastwritetime for the filename   
     $LastWriteDateTime = Get-ItemPropertyValue -Path $file -Name LastWriteTime  
     #Import file and Export   
     Import-Csv $file | ForEach-Object {  
  if ($_.Field1.Trim() -eq '') {  
         $_.Field1 = '--'  
       }  
       if ($_.Field2.Trim() -eq '') {  
         $_.Field2 = '--'  
       }  
       $_  
  } | Export-Csv $newfile -NoTypeInformation -Force  
     Set-ItemProperty -Path $newfile -Name LastWriteTime -Value $LastWriteDateTime  
 }